Finishing machine for concrete surfaces



3 Sheets-Sheet 1 Dec. 10, 1963 R. G. BARNES FINISHING MACHINE FORCONCRETE SURFACES Filed Sept. 12, 1958 5 w m E R 4 N .3 I m 5 e M: i 2 Im N m m A N V N 7 I 3 7 mi N E A v 1 4 Q G S i 0m 9 wt E M om l mm m WINPM m w 13.. Q\ tm *N v )Q 06hr bv V// i I 3 2 mvm o aw mm d mi flm N6 Q;E

Dec. 10, 1963 R. G. BARNES FINISHING MACHINE FOR CONCRETE SUI RF'ACESFiled Sept. 12, 1958 5 Sheets-Sheet 2 INVENTOR Z GLE'N/V 8451/65 10,1963 R. G. BARNES FINISHING MACHINE FOR CONCRETE SURFACES Filed Sept.12, 1958 3 Sheets-Sheet 3 JIE IO INVENTOR. 2 Gt E/VN 54ENE5 UnitedStates Patent 3,113,494 FlNltfililNG MACHENE FGR CONQRETE SURFAQES RalphG. Barnes, Vandalia, ()hio (4361 Wallington Drive, Dayton 40, Ohio)Filed Sept. 12, 1958, Ser. No. 755,180 Claims. (Cl. 9445) This inventionrelates to a finishing machine for concrcte surfaces and moreparticularly to a machine for finishing the surface of freshly laidconcrete paving, however, the invention is not necessarily so limited.

In laying concrete paving, a screed or strike-off bar is employed todoctor the freshly laid concrete surface to the desired elevation orthickness. In conventional practice, the screed is mounted on a mobileapparatus and drawn along the freshly laid pavement immediately as it islaid. Often, to facilitate the operation of the screed it is oscillatedin the direction of its length as it is drawn over the freshly laidpavement.

In addition to the use of screeds or strike-off bars for doctoring thesurface of the freshly laid pavement, it has become conventionalpractice to vibrate the freshly laid concrete. The vibration yields twoimportant results. One is that the concrete material is compacted toeliminate any voids in the concrete body. The other is that a layer ofgrout is brought to the surface of the pavement to enable fin alfinishing as desired.

A vibratory screed capable of 'doctoring the freshly laid pavement tothe desired thickness and also having the desired vibratorycharacteristics for compacting the pavement is disclosed in my UnitedStates Letters Patent No. 2,542,979 issued February 27, 1951, andentitled Screeds for Cement Surfaces. Screeds of the type disclosed inthe aforementioned patent have vastly simplified the apparatus requiredfor finishing concrete pavement. A limitation common to this type ofequipment, however, is that it cannot easily :be adjusted to finish roadbeds of varying width and varying crown. Equip ment which can beadjusted to vary road width and crown tends to be quite massive and forthis reason is unacceptable in many applications, such as bridge deckfinishing.

An object of this invention is to provide a finishing machine forconcrete surfaces which is sufficiently light in weight that it may beused for finishing bridge decks and the like.

Another object of this invention is to provide in a finishing machinefor concrete surfaces an improved vibratory element for compacting theconcrete surface.

Another object of this invention is to provide an improved strike-offbar for use in planing or trowcling the surface of freshly laid concretepavement.

Still another object of this invention is the provision of an improvedfinishing machine for concrete surfaces including a strike-off bar whichis adjustable to provide a curvature therein so as to establish a crownin the concrete surface being finished.

A further object of this invention is the provision of an improvedmachine for finishing concrete surfaces including vibratory elements forvibrating and thereby compacting the concrete body, said machine furtherincluding means for adjusting the position of said vibratory elements toaccommodate a crown in the concrete surface which is being finished.

Yet another object of this invention is the provision of a finishingmachine for concrete surfaces including a strike oif bar for planing thesurface to the desired thickness and one or more vibratory members forcompacting the surface which is to 'be finished.

Still a further object of this invention is the provision of a machinefor finishing concrete surfaces including a 3,113,494 Patented Dec. 10,1963 ice strike-oil bar which may be adjusted to provide a crown in theconcrete surface and vibrating elements for cornpacting the concretesurface after it has been dootored by the strike-off bar, the machineincluding means for adjusting said vibratory elements to accommodate thecrown established by said strike-off bar.

Still a further object is to provide a new and improved method forfinishing freshly laid concrete surfaces wherethe surface is planed toprovide a crown therein and vibrated so as to compact the concrete bodywithout substantial destruction of the crown provided therein.

Gther objects and advantages reside in the construction of parts, thecombination thereof, the method of manufacture, and the mode ofoperation, as will become more apparent from the following description.

in the drawings, FIGURE 1 is a perspective view with parts removed toreveal interior detail illustrating the machine of this invention.

FIGURE 2 is a perspective view drawn to reduced scale illustrating aninner truss member employed in the framework of the machine of FIGURE 1.

FIGURE 3 is a perspective view illustrating schematically the structuralassembly of the machine of FIG- URE 1.

FlGURE 4 is a fragmentary end elevational view of the machine of FIGURE1, with the supporting structure removed, illustrating schematically thethe operative elements of the machine.

FIGURE 5 is an elevational view illustrating schematically thearrangement of vibrator elements in the machine of FTGURE 1 forvibrating a pavement having a predetermined crown.

FXGURE 6 is an enlarged front elevational view taken in the direction ofthe line 66 of FIGURE 1.

IGURE 7 is an end elevational view of the vibrator structure illustratedin FIGURE 6.

Fi'GURE 8 is an enlarged end elevational view taken in the direction ofthe line 8-8 of FIGURE 1.

FIGURE 9 is a front elevational view of the structure illustrated inFIGURE 8.

FiGU RE 10 is an enlarged rear elevational view taken substantially inthe direction of the line HF-1t of FIG- URE 1.

Referring to the drawings in greater detail, the machine of thisinvention is illustrated in FIGURE 1. This machine is designed to movelongitudinally along a highway bed behind an apparatus depositing freshconcrete to form the highway. To this end, rails 16 supported bysuitable standards 12 are provided on both sides of the highway. Theconcrete finishing machine is provided with wheels 14 for traveling uponthe rails 19.

On each end of the machine the forward wheel 14, as viewed in FIGURE 1,is supported upon an axle 16 jour' nailed in a lever arm 1'8. The leverarm 18 is pivoted on a pin 2% to a bracket 22 welded to a transversechannel member 24. The arrangement is such that pivotal movement of thelever arm 18 will function to raise and lower the transverse channelmember 24 relative to the forward wheel 14.

A rear wheel 14 on each end of the machine, as viewed in FTGURE l, issupported upon an axle 2s journalled in a lever arm 28. The lever arm 23is pivotally secured by means of a pivot pin 3% to a bracket 32 weldedto the transverse channel member 24. Wheel scrapers 33 secured to thetransverse channel member '24 engage the rims of the wheels 14.

The lever arms 18 associated with the front wheels 14 and the lever arms28 associated with the rear wheels 14 are joined by a connecting link 3The forward end of the link 34 is provided with an elongate slot 36 sothat the lever arm 18 is engaged with lost motion. The assembly of leverarms 13 and 28 together with the linkage 34 is duplicated on each sideof the wheels 14 at each end of the finishing machine. As clearlyillustrated in FIGUIUE 1, the elongate lever arms 28 associated with therear wheels 14 are joined by transverse rungs 29.

The arrangement is such that a pivoting movement of the rear lever arms28 in the clockwise direction, as viewed in FIGURE 1, may be used toelevate the transverse channel member 24 relative to the highway bed,While pivotal movement of the rear lever arms 28 in the reversedirection will function to lower the transverse channel member 24. Thelever arms 28 are shown in the extreme counterclockwise position at theright end of the machine in FIGURE 1 and in the extreme clockwiseposition at the left end of the machine in FIGURE 1.

As best illustrated at the right end of the machine of FIGURE 1, theforward wheel supporting bracket 22 is provided with a plurality ofspaced holes 38 adapted to receive a lock pin 40. Similar holes and alock pin 4i) are provided on the opposite side of the bracket 22. Thelock pins 40 determine the counterclockwise position of the lever arms18. Thus, by rotating the lever assembly in the clockwise direction,then inserting the pins 44 in any of the holes 38, then returning thelever assembly to its counterclockwise position, the lock pins 40 may beused to support the lever arms 18 in a predetermined intermediateposition such that the forward end of the channel member 24 is elevated.The lost motion slot 36 in the links 34 will permit fullcounterclockwise travel of the lever arms 28, however, such that therear end of the channel member 24 will not be correspondingly elevated.Similar locking mechanism is provided on the left end of the machine.

The levers associated with the wheels 14 at each end of the finishingmachine thus provide a means for elevating the channel members 24 asdesired and for selectively retaining the forward ends of the channelmembers 24 at anelevated position.

The transverse channel members 24 at either end of the machine of FIGURE1 support a telescoping truss assembly as described in the following.Secured in spaced relation to the channel member 24 at the right end ofthe machine of FIGURE 1 is a rectangular outer trust assembly 42comprising parallel upright trusses 42a and 42b. The top portions ofthese trusses are supported in fixed spaced relation by transverse anglebars such as identified in the drawings by reference numerals 44a, 44b,and 440. The bottom of the trusses 42a and 42b are connected in spacedrelation by channel members such as illustrated at 46a and 46b in FIGURE1.

The tranverse channel member 24 at the left end of the machine of FIGURE1 supports a similar outer truss assembly 48 comprising parallel uprighttrusses 48a and 48b. These trusses 48a and 48b are supported in fixedspaced relation at their tops by transverse angle bars such asdesignated by the reference numerals 58a, 559b, and 590. At theirbottoms, these trusses 48a and 48b are connected by transverse channelmembers such as illustrated at 52:: and 52b in FIGURE 1.

The rectangular outer truss assemblies 42 and 43 provided at each end ofthe machine of FIGURE 1 telescopically receive a rectangular inner trussassembly 54 illustrated in FIGURE 2. This inner truss assembly has beenomitted from the machine as illustrated in FIGURE 1 to avoid confusionof detail. With reference to FIGURE 2 the inner truss assembly 54comprises parallel upright side trusses 56a and 56b secured in spacedrelation by angle bars indicated by the reference numerals 58a, 58b, 58cand 58d at the top, and by end braces represented by the numerals 60aand 60b at the bottom. The angle bars which make up this inner trussassembly 54 each have their flanges turned inwardly so that this innertruss assembly will slide freely in the outer truss assemblies of FIG-URE l.

The telescoping arrangement of the truss assemblies is illustrated inFIGURE 3, There it will be observed that the inner trus assembly 54projects into the ends of the outer truss assemblies 42 and 4S much likethe inner slide of a conventional match box. The arrangement is suchthat the length of the machine illustrated may be varied from a minimumrepresented by the combined lengths of the trusses 42 and 48 to amaximum represented by the combined lengths of the trusses 42 and 48plus about four-fifths of the length of the truss assembly 54. At themaximum extension of the machine, the end portions of the truss assembly54 must project into the ends of the assemblies 42 and 48 a sufiicientdistance to provide support for the outer truss assemblies 42 and 48. Atany given extension the truss assemblies are all bolted together to makea rigid structure.

The primary operative elements of the machine of this invention areillustrated in FIGURE 4. This figure depicts schematically and inphantom detail the assembly of wheels 14 with the transverse channelmember 24 at one end of the machine. The machine is positioned above aconcrete deposit designated by the reference numeral 62. At the forwardend of the machine a strikeoff bar 64 is supported in contact with theconcrete surface. This bar 64 is of a general L-shaped sect-ion and isprovided with a scoop 66 at the forward end thereof for planing thesurface of the concrete deposit 62.

To the rear of the strike-off bar 64 the machine supports a pair of likeelongate vibratory beams 63a and 685. Only one of the beams 68a isillustrated in FIGURE 4. This beam has a substantial L-shaped sectionand is provided with a trailing flange 7% adapted to slap the surface ofthe concrete deposit 62 thereby to compact the deposit.

The machine is adapted to be moved so as to pull the strike-off bar 64in advance of the vibratory beam 68a along the concrete deposit as it isbeing formed, and to this end there is provided, at each end thereof, ahand winch 72 mounted upon a post 74-. The posts- 74 are secured at theends of the machine to the forward ends of the channel members 24. Thewinch cable 76 is adapted for connection to any suitable stationaryobject forward of the machine so that the winches 72 may be operatedmanually to draw the finishing machine across the surface of the freshlylaid concrete deposit at the desired speed. Where desired, poweredwinches may be substituted for the hand winches. The use of winches isfound preferable to the provision of power directly at the wheels 14-for the reason that the weight of the machine is insufficient to provideadequate traction for these wheels.

The vibratory beams 68a and 68b and the supporting structure thereforwill now be described in detail. With reference to FIGURE 1, bothvibratory beams are illustrated. The construction of these beams isidentical. As best illustrated in FIGURE 7, the vibratory beam 68a isformed of an elongate sheet folded to substantially an L-shaped section.Preferably, the vibratory beams are formed of a flexible sheet metalmaterial which may be heavy gauge sheet steel, as an example.

With the metal sheet of the beam 68a folded to an L-shaped section, twoflanges are identifiable. One of these is the flange 7-0, which is sopositioned "as to engage the concrete surface which is being finished inface to face contact. The other is a flange 89 which is oriented uprightor normal to the surface of the concrete. The flanges 70 and 80 arejoined by an arcuate portion or crease 82. The upper margin of theupright flange 80 is provided with a reinforcing rib 84 formed by alength of rigid pipe welded thereto.

The structure for securing the vibratory beam 68a to the finishingmachine includes a clamp assembly 86 which is visible near the center ofthe finishing machine, as illustrated in FIGURE 1. This clamp assemblyand the supporting structure associated therewith is best observed inFIGURES 6 and 7. As clearly illustrated in these figures, the clampassembly 86 engages the reinforcing rib 84 for the vibratory beam 68a.The gripping action of the clamp assembly is controlled by a hexagonalnut 88.

With reference particularly to FIGURE 6, a bracket 90 is bolted to theclamp $6 by means of bolts 92. The bracket 9% is resiliently connectedto a complementary bracket 94- by means of an elastomeric mountingmember as. To this end a bolt 93 engaging the bracket 90 is embedded inthe elastomeric element 96 at the top thereof. The bottom of theelastomeric element is welded to a metallic plate i452 secured to thebracket 94 by means of a bolt fill Through this construction, thebracket 90 and its complementary bracket 94 are resiliently joinedtogether such that the bracket 9% and the vibratory beam 68a supportedthereby may vibrate independently of the bracket 94.

As best seen in FIGURE 7, the bracket es supports a pair of downwardlyextending angle bars 1% which, in turn, support elastorneric bumpersres. These bumpers Title function to support the vibratory beann 6811against the drag of the concrete surface being finished.

The bracket 94 is supported in adjustable relation to the outer trussassembly 4-2 through the use of telescoping tubular members 1% and libbest seen in FIGURE 6. The member 1% is welded at its lower end to thebracket 94 and slides into the member 11%} which, as will be describedsubsequently, is fixedly secured with relation to the inner truss 54.The tubular members 168 and 11h? are arranged vertically. A clamp,indicated genorally by the reference numeral 112, engaging the lower endof the tubular member lid is provided for locking the iembers 1% andill? in fixed telescopic relation.

A bushing 114 provided in the top of the tubular men ber lid rotatablyreceives a vertical screw lifting element 116 extending axially therein.The screw element 116 is retained at a fixed vertical elevation withinthe tubular member 110 by means of a collar 11% secured by a pin 12% andbearing against an annular ring 121 which, in turn, bears against thebushing TM. The extreme upper end of the screw element 116 is squaredoff at 122. for engagement by a suitable crank handle, not shown.

The screw element 116 engages an internally threaded portion 124 of thetubular member 168, such that upon rotation of the screw element its,the tubular member 103 may be adjusted vertically upwards or downwardsdepending upon the direction of rotation of the screw element 116. Thetubular member 'lltl is rigidly secured as follows.

A rectangular plate 126 is welded in face contacting relation to theouter wall of the tubular member Tilt}. Bolts 128 secure the plate 126to a transverse channel member 129 which, as appears in FIGURE 2, is anelement of the inner truss assembly 54 Braces 13d and T32 Welded to theplate 126 and the channel member 129, respectively, cooperate toreenforce the connection between these members.

in the foregoing, a vertically adjustable bracket assembly with whichone end of the vibratory beam 68a is secured to the outer truss assemblyhas been described. With reference to FIGURE 1, the extreme right end ofthe vibratory beam 68:: is supported by a similar vertically adjustablelifting assembly identified generally with the reference numeral 136.The lifting assembly 136 is secured to a transverse channel member inthe bottom of the outer truss assembly 42. Thus the vibratory beam 68ais supported at one end by the inner truss assembly 54-, and at theother end by the outer truss assembly 42. Telescopic adjustment of thetruss assemblies 42 and 54 is made permissible by a loosening of thehexagonal nuts 83 associated with the clamps 86 of the bracketassemblies supporting the vibratory beam 68a. This enables the clamps 86to slide on the reinforcing rib $4 of the vibratory beam 68a.

In a similar manner the vibratory beam 6315, which is situated on theleft end of the machine of FIGURE 1,

is supported by vertically adjustable lifting assemblies designatedgenerally by the reference numerals 138 and Mil. The lifting assembly138 is secured to a transverse channel member 139, which as appears inFIGURE 2, is an element of the inner truss assembly 54. The liftingassembly Mil is secured to the transverse channel member 52b of theouter truss assembly 43.

The vibratory beam 53a is set into vibratory motion by means of avibratory element 142, illustrated best in FIGURE 1. The element 142,which comprises a rotatably mounted shaft having an eccentric weightthereon, is of conventional construction and therefore not illustratedin detail. This vibratory element is clamped against the reinforcing rib84 for the vibratory beam 680. A motor 148 driving a belt 150 isutilized for operating the vibratory element.

As best illustrated in FIGURE 4, the motor 148 is mounted upon a plate149. The plate 149 is supported above a parallel plate 146 by means ofelastomeric spacer elements, not shown. The vibratory element 142 isclamped between the plate 146 and the reinforcing rib 84 by U-shapedbrackets 1144 penetrating the flange 3t and Wrapping around thevibratory element 142 to engage the plate 14s.

A duplicate vibratory assembly, designated in FIGURE 1 by the referencenumeral 152, is employed for impartin-g vibration to the vibratory beam68b. Electrical power is supplied to the assemblies for vibrating thebeams 63a and 6311 by means of an electrical generator 154 secured tothe outer truss assembly 42 at the right end of the machine asillustrated in FIGURE 1. The delivery of electrical power to thevibratory assemblies is controlled by switches 156, illustrated to theright of FIGURE 1.

Due to the nature of the vibratory elements 142 used to impart vibrationto the beams 63a and 6%, each of these beams is urged to vibrate in acircular pattern in a plane normal to the longitudinal axis thereof. Thereinforcing ribs 84 associated with the vibratory beams preventlongitudinal flexing of the vibratory beams thereby insuring that thebeams vibrate uniformly in a circular pattern throughout their length.

The operation of the finishing machine is such as to draw the vibratorybeams 68:; and 681; over the surface of fresh concrete with the flanges7d of the beams trailing the upright flanges 85 thereof. Due to the dragof the concrete on the trailing flange 7-8, the upright flange 8t) isdrawn against the adjacent bumpers ms. The bumpers Hi6 yield under theforce created by drag on the flanges '70 until the elastic restoringforces therein counteract the drag force. These opposing forces bias theflanges Ell to an equilibrium vertical position. The bias is resilientor yieldable such that these flanges remain free to vibrate. Since theimpressed vibration is rotary the flanges ill will vibrate with a rotarymovement.

The rotary vibratory movement of the flanges fill is transmitted to theflanges 70. These flanges therefore also vibrate with a rotary motion.Thus, the flanges 7i will oscillate with a generally horizontal side toside motion and will simultaneously execute a vertical pivotal movement.Due to the vertical pivotal movement, the arcuate creases 82 between theflanges 70 and 80 of the beams 625a and 68b undergo repeated flexingsuch that the angle between the flanges 70 and 80 increases anddecreases cyclically. It is to be observed that the creases 32 are inthe form of a gentle curve as opposed to a sharp angular bend. Thisspreads the flexure of the metal in the creases over a wide area therebyreducing the susceptability of the metal in the creases to workhardening and fatigue.

Preferably, the rest angle between the flanges 7t and 86 is about 93. Anangle in excess of 90 causes the flanges '76} to be inclined to thesurface of the concrete deposit so that they will ski over the concretesurfaces.

7 The skiing action of the flanges 7t enables the vibratory deposit sothat they will ski over the concrete surface. with a minimum ofdistortion of the crown placed thereon.

In practice a condition of resonance develops between the vibratorymovement of the beams 68a. and 68b and the impressed vibratoryfrequency. The condition of resonance is particularly noticeable in theflanges 70 which vibrate with a much greater amplitude than that foundin the movement of the vibratory element 142.

The large amplitude vertical vibration of the flanges 70 produces aslapping or Whipping action such that the surface of the concretedeposit 62 is repeatedly struck with great force. This induces vibrationin the concrete body as illustrated schematically in FIGURE 4.Preferably, the impresed vibratory frequency is in the range of 70*9Ocycles per second.

The vibrations induced in the concrete body are duofunctional. First,they compact the freshly laid concrete eliminating any voids therein.Second, a layer of grout is brought to the surface of the concretedeposit to enable final finishing to be done quickly.

The construction of the strike-off bar 64 and the supporting structuretherefor will now be described. As appears in FIGURE :1, the strike-offbar 64 is formed of a number of segments identified by the numbers 170a,170b, 170b, 170d, 170e and 1707. The extreme left end of the strike-ofibar 64, as viewed in FIGURE 1, connects to a pair of baffles numbered172a. and 17 2b. The baffle 17% serves as a scraper for the left rail onwhich the machine rides. Similar baflles are provided at the opposite orright end of the strike-01f bar.

The segment 170a. of the strike-off bar is illustrated in detail inFIGURES 8 and 9. Referring to FIGURE 8, which shows the segment 170m inend elevation, it is seen that this segment comprises a unitary sheetfolded so as to have substantially right angularly disposed flanges 174and 1178. The flange 174, which is oriented vertically, has its lowermargin struck outwardly to form a scoop or inclined plane 176. Thesegments 170b, 1700,

170d, 170e, and 1707 are similarly formed and, as appears in FIGURE 1,the inclined planes 176 in each segment align to form a continuousinclined plane sur face for scraping or planing the surface of theconcrete deposit over which the machine is moved.

Referring to FIGURES 8 and 9, the segment 170a of the strike-off bar isreinforced by right angular rib elements 180 and 182 formed from lengthsof angle bar welded together. These rib elements are welded in place onthe segment 17051.. Other reinforcement, not illustrated, may beprovided as required.

The structure for supporting the segment 170a. with respect to thefinishing machine includes a hinge element 1 84 welded to thereinforcing rib elements 180 and 182. This hinge element is pivotallyengaged by a vertically disposed tubular member 186 provided at itslower end with a clevis 188. The tubular member 186 fits telescopicallyinto a larger tubular member 190 and is threadedly engaged by a verticalscrew lifting element 192. The assembly of telescopic tubular members 186 and 190 is substantially identical in construction to the assembly oftelescoping tubular members 108 and 110 illustrated in FIGURE 6 anddescribed hereinbefore.

The tubular member 190 is connected to a channel member 198 which ispart of the outer truss assembly 48. To effect this connection a plate194 is Welded in face contacting relation to the tubular member 190 andbolted to the channel member 198 with bolts 196. A brace 200 welded tothe plate 194 and a brace 202 Welded to the channel member 198 cooperateto strengthen the connection between the channel member 198 and thetubular member 190.

It is evident from the foregoing construction that rotation of the screwlifting element 192 may be employed to raise and lower the segment 17%of the strike-off bar 8 64. In a similar manner, the segment 17012 isconnected by means of an adjustable assembly of telescopic tubularlifting members designated generally by the reference numeral 210 to atransverse channel member 211 .of the outer truss assembly 48. Thesegment 1700, which is substantially at the center of the strike-off bar64, is secured by means of an adjustable assembly of telescoping tubularlifting members designated by the reference numeral 212 to thetransverse channel member 129 of the inner truss assembly 54-. Thesegment 1702 is secured to the transverse channel member 46a of theouter truss assembly 42 by means of an assembly of telescoping tubularlifting members designated by the reference numeral 214. The assembly214 is shown in fragmentary detail. The segment 17th of the strike-offbar 64 is secured by means of an adjustable assembly of telescopingtubular lifting members designated gencrally by the reference numeral216 to a transverse channel member 218 of the outer truss assembly 42.

Adjacent pairs of the segments 17tPa-f are joined in the mannerillustrated in FIGURE 10. Specifically, this figure shows the connectionbetween the segments 17% and To effect the connection, the segment 17012is provided at its end with a right angular reinforcing rib 220 formed10f angle bar stock. A short distance inwardly of its end, the segment17th is provided with a similar right angular reinforcing rib 222. Whenthe segments 170a and 179 are butted together in end-to-end relation,the reinforcing ribs 229 and 2.22 are distributed in parallel relationwith a small gap tberebetwecn. The reinforcing rib 220 is so positionedon the segment 170s that it overlaps the seam between the segments 17%and 170].

The rein-forcing ribs 223 and .222. are bolted together at theiropposite ends by means of bolts 22 i and 226. A hearing 228 ispositioned between these two reinforclinig ribs in the corners thereof.The bearing 228 is secured between the ribs by means of a bolt assembly,not illustrated, the bolt of this assembly passing through the uprightflanges of each of the ribs 226 and 222 and through the center of thebearing 228..

The opposite ends of the bearing 228. are tapered so as to reduce thearea of contact between the ends of the bearing 2128 and the reinforcingribs 220 and 222. By virtue of this reduced area of contact, thesegments 170.2 and 1709 are permitted limited pivotal movement on thebearing 22-8 whenever the bolts 224 and 226 connecting the ends of thereinforcing ribs 22% and 2.22 are loosened. This type of connectionenables the segments 17% and 1701 to be adjusted to a desired angularrelationship with the bolts 224 and 226 loosened, then to be fixed atthat angular relationship by tightening the bolts 224 and A similarconnection is provided between all adjacent segments of the strike-citbar. At those junctions where the segments are supported by anadjustable lifting support, such as the junction between the segments17% and 1706, the upper bolt 22.4 is replaced by an unthreaded shaft. Asa result these adjacent segments are, at all times, free to pivot withadjustment of the lifting support. The arrangement is such that byloosening the connecting bolts between all of the segments of thestrike-off bar and by thereafter adjusting the elevation of thestrikeoff bar by means of the adjustable lifting supports for thesegments 170a, 1170b, 1700, 1702 and 170 the strike-off bar may beformed to a desired curvature in the vertical plane. Once the desiredcurvature has been established, it may be fixed by tightening the boltsjoining the ends of adjacent segments. With this type of assembly, thestrike-off bar 64- may be adjusted within reasonable limits to place anydesired crown on the concrete surface which is to be finished.

I The adjustable lifting supports for the strike-off bar 64 have asecondary function. It is not possible as a practical matter to preservethe adjustment of the finishing machine indefinitely. The adjustablelifting supports permit adjustment to correct small errors in thealignment of the strike-off bar as they develop.

The operation of the finishing machine will now be described. With thefinishing machine situated upon rails over the surface which is toreceive a concrete finish, the strike-oil bar 64 is adjusted to providethe desired crown in the concrete surface by adjusting the variousadjustable telescoping lifting assemblies 1%, 211i 212, 214- and 216.The bolts connecting the ends of the strike-cit bar segments, which areloosened to permit the initial adjustment of the strike-off bar, arethereafter tightened to fix the curvature of the strike-off bar. Thestrike-off bar is then adjusted to the desired elevation relative to theground through adjustment of the pins 40 in the holes 38 of the brackets22 at the opposite ends of the finishing machine. This latter adjustmentis accomplished without altering the crown setting. Usually, thestrike-oil bar is set /2 inch or so above the desired surface elevationto allow for subsequent compaction.

The vibratory beams 63a and 6% are adjusted to accommodate the crown ofthe concrete surface. This adjustment is eilected by adjustment of thetelescoping lifting assemblies 11-6, 136, 1 38, and l id). FIGURE 5illustrates the manner in which the vibratory beams 68:: and 68]) areadjusted to accommodate the crown of the concrete surface. In thisfigure the shape of the crown is illustrated schematically by the brokenrcuate line 249. The vibratory beams 68a and 6812, which are alwaysmaintained in overlapping end-to-end relation, are adjusted so that thepoint at which their flanges 7% cross is at the top of the crown whenthe opposite ends of the beams 68a and 68b also lie on the surface ofthe crown. Preferably, the aforementioned points are set about Mr inchbelow the ultimate crown surface. This insures effective action of thevibratory beams throughout the entire width of the concrete surfacebeing formed. The arcuate crease 82 in each vibratory beam functions toguide the upper portions of the concrete surface under the flange 70.

Following the adjustments outlined in the foregoing, the generator 154is put into operation so that the vibratory beams 63a and 68b arecontinuously vibrated. As concrete is poured forward of the machine, themachine is advanced at a uniform rate to finish the concrete.Preferably, the elevation of the concrete placed in front of the machineis such that a roll of approximate 2 inches height will be maintained infront of the strike-oil bar at all times.

it has been found that this concrete finishing machine will operatecontinuously for long periods of time with out attention. At any time,as for example when it may be desired to make small adjustments on themachine or to discontinue the operation of the machine, both thestrike-off bar 64 and the vibratory beams 68a and 63b may be picked upoil the concrete surface by movement of the lever arms 23 at theopposite ends of t e finishing machine in the counterclockwise directionas viewed in FIGURE 1.

As described hereinbefore, the overall length of the concrete finishingmachine is variable due to the use of telescoping truss assemblies. Theoverall length of the strike-off bar 64 is adjustable by adding orremoving segments, like the segment 170d, which are of varying length.These segments may be added on either side of the segment 170C.Ordinarily, a suflicient number of extra segments is kept on hand sothat the strike-off bar 64 may be adjusted to any of the standard roadwidths between the maximum and minimum widths to which the presentconcrete finishing machine may be adjusted.

The vibratory beams 68a and 68b each have a length slightly exceedingone-half the maximum length of the finishing machine. As a result, evenwhen the machine is adjusted to its maximum width, there will be apartial overlap between the ends of the vibratory beams 68a and.

68b. As noted hereinbefore, the clamping assemblies 86, engaging theoverlapping ends of the vibratory beams, must be loosened so that theymay slide upon the reinforcing ribs 84 whenever the overall length ofthe concrete finishing machine is changed.

Although the preferred embodiment of the device has been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode of operation, which generallystated consist in a device capable of carrying out the objects setforth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. An apparatus for finishing the surface of fresh concrete comprising avibratory beam, structure for supporting said beam upon the concretesurface, said beam comprising a pair of elongate substantially planarflanges, one of said flanges adapted to be normal to the concretesurface and the other of said flanges adapted to be substantiallyparallel to and in contact with said concrete surface, there being amargin of said one flange in proximate relation to a margin of saidother flange, a flexible arcu-ate portion uniting said proximate marginswhereby said beam has a substantially L-shaped section, said structureincluding means engaging said one flange and resiliently supporting saidbeam from said structure for vibratory movement relative to saidstructure, a vibrating unit for transmitting vibratory motion to saidone flange, said arcuate portion having a flexibility sufficient topermit resonant vibration of said other flange about a longitudinal axisdefined by said flexible portion at the frequency of the impressedvibratory motion, said flanges being sufliciently similar in width toaccomplish such vibration, and reinforcing means engaging said beam andextending longitudinally along the length thereof to prevent resonanttransverse vibration of said beam except at frequencies higher than thatof the impressed vibration.

2. An apparatus for finishing the surface of fresh concrete including avibratory beam, said beam comprising an elongate flexible metallic sheetprovided with a longitudinal arcuate crease forming two angularlydisposed flanges thereof, one of said flanges being vertical and theother substantially horizontal, means providing a reinforcing rib alongthe free margin of the vertical flange, and vibratory means engagingsaid reinforcing rib for imparting vibration to said beam, said meansvibrating normal to the longitudinal axis of said beam, said reinforcingrib imparting suflicient rigidity to said beam to prevent resonanttransverse vibration of said beam except at freqeuncies higher than thatimpressed by said vibratory means, and said arcuate crease havingsufficient flexibility to permit resonant vibration of said horizontalflange about a longitudinal axis defined by said crease at the frequencyof vibration impressed by said vibratory means, said flanges beingsufficiently similar in width to accomplish such vibration.

3. llhe apparatus according to claim 2,. wherein said substantiallyhorizontal flange is disposed in trailing relation to said verticalflange at an angle thereto exceeding the arcuate crease therebetweenfunctioning to guide upwardly projecting portions of said concretesurface under said substantially horizontal flange.

4. In an apparatus for finishing the surface of a fresh concretedeposit, an elongate beam, structure for supporting said beam parallelto the surface of said deposit, and means for vibrating said beam, theimprovement wherein said beam comprises an elongate strip of flexiblemetallic material having an arcuate longitudinal crease therein formingtwo angularly disposed flanges thereof, and means providing an elongatereinforcing rib along the free margin of one of said flanges, saidstructure including resilient mounting means engaging said reinforcingrib to support said beam for independent vibratory motion, said oneflange adapted to be oriented substantially normal to the plane of saidconcrete surface and supporting said vibratory means, the other flangehaving one face adapted to contact said concrete surface, saidreinforcing rib imparting suflicient rigidity to said beam to preventresonant transverse vibration of said beam except at frequencies higherthan that impressed by said vibratory means, and said arcuate creasehaving sufficient flexibility to permit resonant vibration of said otherflange about a longitudinal axis defined by said crease at the frequencyof vibration impressed by said vibratory means, said flanges beingsufficiently similar in width to accomplish such vibration.

5. An apparatus for finishing the surface of a fresh concrete depositincluding a vibratory beam, structure for supporting said beam upon saiddeposit, said beam including a pair of elongate flanges of flexiblematerial arranged at an angle and united by an arouate flexible portionso as to have a substantially L-shaped section, and means providing anelongate reinforcing rib along the free margin of one of said flanges,vibratory means engaging said rib to vibrate said beam, said structureincluding a supporting bracket, a complementary bracket engaging saidreinforcing rib, and an el-astomeric body joined to both said bracketsproviding a resilient connection therebetween, said brackets supportingthe reinforced flange of said beam substantially normal to the surfaceof said concrete deposit, the other flange of said beam adapted to bedisposed in face contacting relation to said concrete deposit, saidreinforcing rib imparting suflicient rigidity to said beam to preventresonant transverse vibration of said beam except at frequencies higherthan that impressed by said vibratory means, and said arcu ate flexibleportion having sufiicient flexibility to permit resonant vibration ofsaid other,

12 flange about a longitudinal axis defined by said flexible portion atthe frequency of vibration impressed by said vibratory means, saidflanges being sufficiently similar in Width to accomplish suchvibration.

References Cited in the file of this patent UNITED STATES PATENTS1,386,348 Mlaxon Aug. 2, 1921 1,388,690 Baker Aug. 23, 1921 1,619,083Maxon Mar. 1, 1927 1,662,257 Valerio Mar. 13, '1928 1,782,707 BayileyMay 25, 1930 1,987,398 Gardiner Jan. 8, 1935 2,072,479 Hadley Mar. 2,1937 2,094,910 Baily Oct. 5, 1937 2,145,959 Venable Feb. 7, 19392,150,618 Blackwell Mar. 14, 1939 2,219,246 Jackson Oct. 22, 19402,306,125 Jackson Dec. 22, 1942 2,332,687 Baily Oct. 216, 1943 2,346,378Jackson Apr. 11, 1944 2,351,593 Barber June 20, 1944 2,542,979 BarnesFeb. 27, 1951 2,681,231 Kondracki June 15, 1954 2,693,136 Barnes Nov. 2,1954 2,951,426 Pollitz Sept.,6, 1960 FOREIGN PATENTS 831,023 France May30, 1938 142,458 Australia July 25, 1951 OTHER REFERENCES ConstructionMethods and Equipment, September 1953, page 128.

2. AN APPARATUS FOR FINISHING THE SURFACE OF FRESH CONCRETE INCLUDING AVIBRATORY BEAM, SAID BEAM COMPRISING AN ELONGATE FLEXIBLE METALLIC SHEETPROVIDED WITH A LONGITUDINAL ARCUATE CREASE FORMING TWO ANGULARLYDISPOSED FLANGES THEREOF, ONE OF SAID FLANGES BEING VERTICAL AND THEOTHER SUBSTANTIALLY HORIZONTAL, MEANS PROVIDING A REINFORCING RIB ALONGTHE FREE MARGIN OF THE VERTICAL FLANGE, AND VIBRATORY MEANS ENGAGINGSAID REINFORCING RIB FOR IMPARTING VIBRATION TO SAID BEAM, SAID MEANSVIBRATING NORMAL TO THE LONGITUDINAL AXIS OF SAID BEAM, SAID REINFORCINGRIB IMPARTING SUFFICIENT RIGIDITY TO SAID BEAM TO PREVENT RESONANTTRANSVERSE VIBRATION OF SAID BEAM EXCEPT AT FREQUENCIES HIGHER THAN THATIMPRESSED BY SAID VIBRATORY MEANS, AND SAID ARCUATE CREASE HAVINGSUFFICIENT FLEXIBILITY TO PREMIT RESONANT VIBRATION OF SAID HORIZONTALFLANGE ABOUT A LONGITUDINAL AXIS DEFINED BY SAID CREASE AT THE FREQUENCYOF VIBRATION IMPRESSED BY SAID VIBRATORY MEANS, SAID FLANGES BEINGSUFFICIENTLY SIMILAR IN WIDTH TO ACCOMPLISH SUCH VIBRATION.